The present invention relates to an endoscope including a plurality of cover members, of which each is arranged to cover a connection portion where the soft member constituting the insertion portion, cord, etc. of the endoscope is connected with the hard member constituting the control portion, connectors, etc. of the endoscope.
Description of the Related Art
The endoscope is generally composed of the following constituents, that is, an insertion portion which is inserted in the somatic cavity, a control portion successively connected with the base end portion of the insertion portion, and a connector connected with the control portion by means of the cord. The soft portion which constitutes the base end portion of the insertion portion and the cord are made of a soft member while the control portion and the connector are made of a hard member. The connection portion between the soft member and the hard member is covered with such a cover member that protects the soft member from being crushed or snapped. In general, this cover member is made of a resilient member such as rubber. FIG. 7 of the accompanying drawings is a schematic sectional view showing the connection portion between the insertion portion and the control portion and its surroundings of the conventional endoscope. A cylindrical member 10 constituting the soft portion is connected with a sleeve 20 constituting a part of the control portion. The cover member 30 is set to cover the outside of this connection portion.
The end portion of the cover member 30, which is positioned on the insertion portion side, comes in close contact with the outer surface of the cylindrical member 10. The inside surface near the center portion of the cover member 30 comes in contact with the end portion of the sleeve 20, and the airtightness of this portion is secured by a O-ring 40 which is arranged in the groove portion formed in the sleeve 20. A case member 50 is put on the outer circumference on the base end side of the cover member 30, and the airtightness of this portion is secured by a O-ring 42 which is arranged in the groove portion 34 formed on the outer circumference on the base end side of the cover member 30. A threaded portion is formed along the inner circumference of a portion where the groove portion 34 is formed. This threaded portion is screw-joined with the threaded portion formed on outer circumference of the sleeve 20, thereby the cover member 30 being joined together with the control portion. On one hand, the case member 50 is clamped immovably in the axial direction by means of a check ring 60 which is screw-joined with the threaded portion of the sleeve 20. In case of a certain cover member 30, the base end side member where the O-ring 42 is arranged, some threaded portion is formed and so forth, is made of a metallic material while the tip end side portion connected with that base end side member is made of a resilient material such as rubber.
As described above, in general, the cover member includes a threaded portion formed on the inner circumference surface of the based end portion. This threaded portion is screw-joined with the hard member thereby fixing the cover member to the hard member. As a related art with regard to the cover member, the Japanese Patent Laid-open Publication No. 2000-152910 discloses a cover member in which there is provided a restraint means making it impossible for the cover member to rotate.
By the way, in the process of cleaning the endoscope, it happens that the operator unintentionally turns the cover member while he wipes out water remaining on the cover member. However, in case of the cover member as shown in FIG. 7, since it is fix by the screw-joint, there is a possibility that the screw-joint is loosened, which in turn might cause airtight failure or the like.
Furthermore, in case of that which was disclosed by the above-mentioned publication, that is, in case of the endoscope provided with the restraint means a making it impossible for the cover member to rotate, when the operator strongly turns the cover member, especially the operator familiar with the conventional structure turns the cover member excessively, there is fear that structural parts might be broken.